This invention relates to an aquarium receptacle comprising a habitat for fishes to be filled with water and a water purification system.
The keeping of fishes and in particular of tropical marine fishes and lower animals requires a substantial purification of the aquarium water. Aquarium water purification generally is effected by passing the water through one or more filters, wherein dirt particles are retained by mechanical filtration. The filter medium, consisting of wadding, gravel, sand or carbon grains, is spontaneously colonized by bacteria, which biologically purify the water.
In most existing systems the filters are accomodated in special filter pots or in receptacles situated outside the aquarium, and the water is siphoned and circulated by means of hoses or pipes and one or more pumps. Alternatively, loose filter chambers can be placed within the aquarium or the chambers are attached to a sidewall or to the rear wall of the aquarium or are built in.
For a more complete purification, the water can additionally be passed through a so-called protein skimmer, thereby forming, by means of finely divided air, supplied countercurrently to the aquarium water, a foam layer which is separated. For this purpose separate devices are suspended in the aquarium or placed outside the aquarium.
For a further perfection, anaerobic biological filtration can be employed. To that end, a small part of the circulating water is passed through a filter wherein nitrate is converted to nitrogen gas, without admission of oxygen.
These separate systems all have the drawback that for a complete treatment a plurality of installations is required that are to be interconnected in such a manner that the throughflow in each system is optimal. The existing separate units are often not optimally attuned to each other and to the aquarium. Various pipes are necessary and often a plurality of pumps, each of which can get detached, become clogged or get otherwise deranged. The aggregate of installations has no pleasant appearance and occupies much space.
According to a known system, a plurality of communicating chambers are created in the aquarium by means of partitions, siphons and grids. This system has the drawback that the water is removed from the bottom of the aquarium via a perforated bottom plate or otherwise. However, at the surface of the aquarium water a film of bacteria algae and proteins is formed, which is not removed by this system. The system described, moreover, utterly fails to provide for optimum mutual attuning of the different filtration processes by a sophisticated arrangement and design of the chambers.
Another known per se arrangement within the aquarium space concerns the bottom filter. That system also has the drawback that the surface is not purified. The system is prone to clogging and cannot be cleaned without emptying the aquarium. The bottom filtration alone is absolutely insufficient for the marine aquarium.
According to a known filtration method, filter cartridges are used that consist of two helically wound materials of different structures. These `Double Layer Spiral` or DLS filters, can be accomodated in filter chambers in different manners. By means of these filters, mechanical filtration, aerobic biological filtration as well as anaerobic biological filtration can be obtained. However, it is not known whether and how the filters could be arranged to combine the various functions with a protein skimmer in such a compact manner that the entire water purification system can be accomodated in the aquarium itself.